This invention relates to a drive mechanism for a vehicle trailer lifting gear and to a vehicle trailer provided with such a mechanism. The drive mechanism is suitable for a vehicle trailer lifting gear, hereinafter termed "of the kind defined", in which telescopic support legs are provided, at the trailer end couplable to a vehicle, for supporting the uncoupled trailer end relative to the ground and operable via a rotatable shaft and gearing, to vary the height of said trailer end to permit coupling to or uncoupling from a vehicle. Generally such support legs are wheeled.
Conventionally lifting gear of the kind defined is operated manually by turning a handle attachable to one end of the rotatable shaft, thus extending or retracting the support legs as desired via the gearing acting on the legs. Such manual operation is both time consuming and tiring to the operator and can cause undesirable delays in coupling and uncoupling the trailer and vehicle. Whilst proposals have been made to provide mechanical drive means for the lifting gear such as by substituting hydraulic piston and cylinder or air ram assemblies for the gear driven telescopic legs, such proposals have not provided an economic or effective solution to the problem. In particular such proposals require expensive easily damaged components and the existing sturdy conventional lifting gear legs have to be removed from the trailer before these components can be fitted.
There is thus a need for a generally improved drive mechanism for vehicle trailer lifting gear of the kind defined which can be fitted to existing trailers with minimum alteration.
According to one aspect of the present invention there is provided drive mechanism for a vehicle trailer lifting gear of the kind defined, including an air driven rotary drive unit fixedly attachable to the vehicle trailer and connectible to a source of air under pressure, and means for drivingly connecting the drive unit to one end of the rotatable shaft so that with the mechanism in operative association with the vehicle trailer the drive unit can be connected to the source of air pressure to rotate the shaft one way or the other to extend or retract the support legs.
According to another aspect of the present invention there is provided a vehicle trailer having lifting gear of the kind defined and drive mechanism as hereinbefore described, in which the nut is welded to said one end of the rotatable shaft, the drive unit is bolted to the bracket, the bracket is welded to one of the support legs with the socket in engagement with the nut, the air hose is connected at one end to the drive unit and at the other end to the male hose coupling and the male hose coupling attached to the trailer connected board for connection to a secondary air braking system of a vehicle.
For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings.